递归和非递归分别实现求第n个斐波那契数

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<Windows.h>
#include<string.h>

//  非递归实现
int fib_2(int n)
{
int a = 1;
int b = 1;
int c = 0;
if (n <= 2)
{
return 1;
}
while (n > 2)
{
c = a + b;
a = b;
b = c;
n--;
}
return c;
}

//   递归实现
int fib_1(int n)
{
if (n <= 2)
{
return 1;
}
return fib_1(n - 1) + fib_1(n - 2);
}

int main()
{
int n = 0;
scanf("%d", &n);
printf("%d\n", fib_1(n));
printf("%d\n", fib_2(n));
system("pause");
return 0;
}